#include <avr/io.h>
#include <util/delay.h>
#include <stdint.h>
#include <avr/interrupt.h>
#include <stdlib.h>
#include "pcf8591.h"

#define F_CPU 8000000L

/* PCF8591 address, max SCL clock frequency and WRITE and READ definitions */
#define PCF8591_ADDR  0x48
#define TWI_BITRATE   100000
#define TWI_WRITE     0
#define TWI_READ      1
#define BAUD_PRESCALER (F_CPU/(BAUDRATE*16UL) - 1 )
#define BAUDRATE 9600

void USART_INIT(void)
{
	// This function will set the micro controller for serial communication with the PC
	// It sets the necessary baud rate registers, and prescaler value.
	UBRR0H = (uint8_t)(BAUD_PRESCALER >> 8);
	UBRR0L = (uint8_t)(BAUD_PRESCALER);
	UCSR0B = (1 << RXEN0) | (1 << TXEN0);
	UCSR0C = (3 << UCSZ00);
}
void USART_SEND(unsigned char data)
{
	// Function to send data from the ATmega328P to the terminal on the PC
	while(!(UCSR0A & (1 << UDRE0)));
	UDR0 = data;
}
unsigned char USART_RECEIVE(void)
{
	// This function receives data from the PC Terminal through
	// the USB cable.
	while(!(UCSR0A & (1<<RXC0)));
	return UDR0;
}

unsigned char Change_case(unsigned char letter)
{
	// Function to change the case of the received character
	// Example: if an a was received, the function will return an A
	// Example: if an A was received, the function will return an a
	unsigned char temp;
	if(letter & 32)
	{
		temp = letter - 32;  //If 32nd bit is 1, it was a lower case letter
	}
	else
	{
		temp = letter + 32; //If 32nd bit is 0, it was an upper case letter
	}
	return temp;               // Return the converted ASCII char.
}



uint8_t sine_wave[256] = {
	0x80, 0x83, 0x86, 0x89, 0x8C, 0x90, 0x93, 0x96,
	0x99, 0x9C, 0x9F, 0xA2, 0xA5, 0xA8, 0xAB, 0xAE,
	0xB1, 0xB3, 0xB6, 0xB9, 0xBC, 0xBF, 0xC1, 0xC4,
	0xC7, 0xC9, 0xCC, 0xCE, 0xD1, 0xD3, 0xD5, 0xD8,
	0xDA, 0xDC, 0xDE, 0xE0, 0xE2, 0xE4, 0xE6, 0xE8,
	0xEA, 0xEB, 0xED, 0xEF, 0xF0, 0xF1, 0xF3, 0xF4,
	0xF5, 0xF6, 0xF8, 0xF9, 0xFA, 0xFA, 0xFB, 0xFC,
	0xFD, 0xFD, 0xFE, 0xFE, 0xFE, 0xFF, 0xFF, 0xFF,
	0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFE, 0xFD,
	0xFD, 0xFC, 0xFB, 0xFA, 0xFA, 0xF9, 0xF8, 0xF6,
	0xF5, 0xF4, 0xF3, 0xF1, 0xF0, 0xEF, 0xED, 0xEB,
	0xEA, 0xE8, 0xE6, 0xE4, 0xE2, 0xE0, 0xDE, 0xDC,
	0xDA, 0xD8, 0xD5, 0xD3, 0xD1, 0xCE, 0xCC, 0xC9,
	0xC7, 0xC4, 0xC1, 0xBF, 0xBC, 0xB9, 0xB6, 0xB3,
	0xB1, 0xAE, 0xAB, 0xA8, 0xA5, 0xA2, 0x9F, 0x9C,
	0x99, 0x96, 0x93, 0x90, 0x8C, 0x89, 0x86, 0x83,
	0x80, 0x7D, 0x7A, 0x77, 0x74, 0x70, 0x6D, 0x6A,
	0x67, 0x64, 0x61, 0x5E, 0x5B, 0x58, 0x55, 0x52,
	0x4F, 0x4D, 0x4A, 0x47, 0x44, 0x41, 0x3F, 0x3C,
	0x39, 0x37, 0x34, 0x32, 0x2F, 0x2D, 0x2B, 0x28,
	0x26, 0x24, 0x22, 0x20, 0x1E, 0x1C, 0x1A, 0x18,
	0x16, 0x15, 0x13, 0x11, 0x10, 0x0F, 0x0D, 0x0C,
	0x0B, 0x0A, 0x08, 0x07, 0x06, 0x06, 0x05, 0x04,
	0x03, 0x03, 0x02, 0x02, 0x02, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x03,
	0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x0A,
	0x0B, 0x0C, 0x0D, 0x0F, 0x10, 0x11, 0x13, 0x15,
	0x16, 0x18, 0x1A, 0x1C, 0x1E, 0x20, 0x22, 0x24,
	0x26, 0x28, 0x2B, 0x2D, 0x2F, 0x32, 0x34, 0x37,
	0x39, 0x3C, 0x3F, 0x41, 0x44, 0x47, 0x4A, 0x4D,
	0x4F, 0x52, 0x55, 0x58, 0x5B, 0x5E, 0x61, 0x64,
	0x67, 0x6A, 0x6D, 0x70, 0x74, 0x77, 0x7A, 0x7D
};
int i = 0;
int main(void){
	TCCR2A = 0x00;		//timer 2 normal mode
	TCCR2B = 0x01;	    //pescaler = 1024
	TIMSK2 = 0x02;		//enable OCR2A compare flag
	OCR2A = 127;
	TIMSK1 = (1<<OCF1A);
	
	ADCSRA = 0x87;					//enable adc, prescaler = 128
	ADMUX = 0x47;					// 5.0V External Reference, Left Adjust = off, using ADC7
	sei();
	USART_INIT();
	char adcStr[6] = "ADC: ";
	char buff[10];
	int j = 0;
	while(1)
	{
		ADCSRA |= (1<<ADSC);			// start conversion
		while((ADCSRA&(1<<ADIF))==0);
		OCR2A = ADC/4.02;
		
		
		USART_SEND('\r');
		USART_SEND( '\n');
		if(OCR2A > 214 && OCR2A <= 173)
			TCCR2B = 0x04;
		if(OCR2A < 173 && OCR2A >= 132)
			TCCR2B = 0x03;
		if(OCR2A < 132)
			TCCR2B = 0x02;
		

		else
			TCCR2B = 0x01;
	}
	 return 0;
}
ISR(TIMER2_COMPA_vect)
{
	if(i == 256)
		i = 0;
	pcf8591_analog_write(sine_wave[i]);
	i++;	
} 